CLINICAL ARTICLE J Neurosurg Spine 29:85–91, 2018 S pinal dural arteriovenous fstulas (dAVFs) are caused by an arteriovenous shunt between one or more branches of a dural artery and the medullary venous system. They are often from dural arteries supply- ing the dural root sleeve and adjacent spinal dura and a draining medullary vein that drains the coronal venous plexus. 4,13 This leads to retrograde flling of the venous plexus with subsequent congestion, dilation, and venous hypertension within the spinal cord, resulting in edema, reduced perfusion, and ischemia of the cord causing a slow and progressive myelopathy. 1,9 Patients generally present with chronic and progressive gait instability and motor and sensory symptoms in the lower extremities. 10 There is often a discrepancy between the location of a dAVF and symptomatology, suggesting that the site of venous drain- age determines clinical presentation. 8,11 Due to the relative ABBREVIATIONS ALS = Aminoff-Logue Scale; dAVF = dural arteriovenous fistula; ICG = indocyanine green; MRC = Medical Research Council. SUBMITTED September 4, 2017. ACCEPTED November 16, 2017. INCLUDE WHEN CITING Published online April 20, 2018; DOI: 10.3171/2017.11.SPINE17988. Timing, severity of defcits, and clinical improvement after surgery for spinal dural arteriovenous fstulas Michael M. Safaee, MD, 1 Aaron J. Clark, MD, PhD, 1 Jan-Karl Burkhardt, MD, 1 Ethan A. Winkler, MD, PhD, 1 and Michael T. Lawton, MD 2 1 Department of Neurological Surgery, University of California, San Francisco, California; and 2 Department of Neurological Surgery, Barrow Neurological Institute, Phoenix, Arizona OBJECTIVE Spinal dural arteriovenous fstulas (dAVFs) are rare vascular abnormalities caused by arteriovenous shunt- ing. They often form at the dural root sleeve between a radicular feeding artery and draining medullary vein causing ve- nous congestion and edema, decreased perfusion, and ischemia of the spinal cord. Treatment consists of either surgical ligation of the draining vein or selective embolization via an endovascular approach. There is a paucity of data on which modality provides more durable and effective outcomes. METHODS The authors performed a retrospective review of a prospectively maintained database by the senior author to assess clinical outcomes in patients undergoing surgical treatment of spinal dAVFs. Preoperative and postoperative motor and Aminoff-Logue Scale (ALS) scores were collected. RESULTS A total of 41 patients with 44 spinal dAVFs were identifed, with a mean patient age of 64 years. The mean symptom duration was 14 months, with weakness (82%), urinary symptoms (47%), and sensory symptoms (29%) at pre- sentation. The fstula locations were as follows: 30 thoracic, 9 lumbar, 3 sacral, and 2 cervical. Five patients had normal motor and ALS scores at presentation. Among the remaining 36 patients with motor defcits or abnormal gait and micturi- tion at presentation, 78% experienced an improvement while the remaining 22% continued to be stable. There was a trend toward improved outcomes in patients with shorter symptom duration; mean symptom duration among patients with clinical improvement was 13 months compared with 22 months among those without improvement. Additionally, rates of improvement were higher for lower thoracic and lumbosacral dAVFs (85% and 83%) compared with those in the upper thoracic spine (57%). No patient developed recurrent fstulas or worsening neurological defcits. CONCLUSIONS Surgery is associated with excellent outcomes in the treatment of spinal dAVFs. Early diagnosis and treatment are critical, with a trend toward improved outcomes. No patient in this study had fstula recurrence or worsen- ing of symptoms. Among patients with abnormal motor or ALS scores, 78% improved after surgery. Therapeutic emboli - zation is an option for some lesions, but for cases with unfavorable anatomy where embolization is not feasible, surgery is a safe option associated with high success. https://thejns.org/doi/abs/10.3171/2017.11.SPINE17988 KEYWORDS spine; dural arteriovenous fistula; surgical outcomes; vascular disorders J Neurosurg Spine Volume 29 • July 2018 85 ©AANS 2018, except where prohibited by US copyright law